1. Field of the Invention
The present invention relates to a video camera device which is most suitably applied to a dome-type video camera device which does not aim at intimidation, is mounted on the ceiling, wall or the like of a building so that it is not conspicuous, and used for the purpose of surveillance while the surveillance is made unnoticed, and particularly belongs to a technical field of an angle adjustment mechanism of a lens.
2. Description of the Related Art
There has been hitherto known a dome-type video camera device which is mounted on the ceiling, wall or the like of a building under unnoticed condition to keep the place under surveillance through video images or sound collection in order to ensure safety in a hospital, a hotel, a department store or the like and enhance service performance.
In this type of the related art dome-type video camera device, a mirror barrel having a lens and a CCD (image pickup element) is secured through an angle adjustment to the front face of a barrel type main body so as to be freely rotatably adjustable in three axial directions, a sound collecting microphone is secured, and a dome-type cover of acrylic resin or the like is detachably secured to the front face of the barrel type main body so that the outer periphery of a movable area of the mirror barrel is covered by the dome-type cover. In the barrel type main body, a front-side chassis of metal plate to which an angle adjustment mechanism is secured is fabricated at the front surface side in the barrel type main body formed of ABS resin or the like, a back-side chassis provided with a connection portion of a coaxial cable which connects the barrel type main body and a monitor in a surveillance room is fabricated at the back surface side in the barrel type main body, and a circuit board is fabricated between the front-side chassis and the back-side chassis in the barrel type main body.
When the dome-type video camera device is mounted on the ceiling, wall or the like of a building, the coaxial cable for connecting the dome-type video camera device and the monitor television in the surveillance room is first connected to the connection portion of the back surface of the barrel type main body, then a rough set-up position of the barrel type main body is set so that the sound collecting microphone faces in a desired direction, and then the barrel type main body is fixed to the ceiling, wall or the like by set screws by the back-side chassis. Subsequently, the lens azimuth (direction and angle) is set to a desired azimuth by the angle adjustment mechanism, the zoom and focus of the lens are adjusted and an image pickup direction and an image pickup range are set while watching a monitor image. At this time, a portable monitor television may be connected to a monitor output terminal by a monitor output cable to ensure the image pickup direction and the image pickup range at a set-up place. Finally, the dome-type cover is secured to the front face of the barrel type main body for the purpose of dustproof, and then a series of set-up works is completed.
The angle adjustment mechanism of the conventional dome-type video camera device is designed by inserting a mirror barrel holder into the outer periphery of the base end (the opposite side to the front surface of the lens) of the mirror barrel, freely rotatably adjustably securing the mirror barrel to the mirror barrel holder at an angle of about 130xc2x0 in a first axial direction which is a direction around the optical axis, freely rotatably adjustably securing the lens holder to the upper portion of the base table and of the lens holder in a second axial direction perpendicular to the optical axis at a symmetrical angle of about 75xc2x0 from the center, and freely rotatably adjustably securing the lens holder base table to the front-side chassis in the barrel type main body at an angle of about 60xc2x0 in a third axial direction which is a direction perpendicular to the second axial direction, thereby forming a three-axes independence type angle adjustment mechanism having three axes fabricated substantially in an oar shape. The sound collecting microphone and the monitor output terminal are secured to the lens holder base table so as to be adjustable in a range of about 60xc2x0.
However, since the related art dome-type video camera device adopts the three-axes independence system for the angle adjustment mechanism of the mirror barrel, the number of parts and the number of fabrication steps are large, the mechanism is complicated and designed in a large size, and the cost is high. Further, since the large-size angle adjustment mechanism is used, the overall size of the dome-type video camera device is large like the diameter thereof is about 120 mm and the height thereof is about 105 mm, and thus it loses its original object that the device is inconspicuously mounted on the ceiling, wall or the like. Further, in the three-axes independence type angle adjustment mechanism, the tip of the mirror barrel cannot be subjected to a swing motion (oscillating motion) at 360xc2x0 with one point of the base end side at the center of the motion. Therefore, when the dome-type video camera device is mounted on the ceiling, wall or the like to set the image pickup direction and the image pickup range, a blind spot of the lens necessarily occurs. Therefore, if a rough set-up device is erroneously set when the dome-type video camera device is first fixed to the ceiling, wall or the like by set screws, a blind spot is liable to occur in a desired image pickup direction and a desired image pickup range even when an angle adjustment of the mirror barrel is made. In this case, a re-setup work for changing the setup device of the dome-type video camera device to the ceiling, wall or the like must be carried out. However, in many cases plaster boards are used for the ceiling, wall, etc., and thus when the re-setup work of the dome-type video camera device is carried out, the plaster boards thereof are liable to be damaged. Therefore, in order to avoid repapering of the plaster boards, it is necessary to secure an attachment between the ceiling, wall or the like and the dome-type video camera device in order to perform a rotational adjustment on the dome-type video camera device, and it causes further increase of the cost. Further, in the three-axes independence type angle adjustment mechanism, since the rotational center in the third axial direction of the mirror barrel is not coincident with the center of the spherical surface of the dome-type cover, there is a problem that when the lens angle adjustment is carried out, the distance between the dome-type cover and the lens is varied and thus large distortion is liable to occur in a pickup image.
The present invention has been implemented in order to solve the above problem, and has an object to provide a video camera device in which a lens angle adjustment mechanism can be designed in a compact size and the structure thereof is simplified.
In order to attain the above object, a video camera device of the present invention includes a ball joint mechanism designed so that a spherical portion provided to the base end of a mirror barrel is joined to a spherical portion supporting table provided to a chassis through a joint ring and the mirror barrel is rotatably adjusted in three axial directions around the center of the spherical portion of the mirror barrel.
In the video cameral device according to the present invention thus constructed, the lens angle adjustment mechanism is constructed by the ball joint mechanism which comprises the spherical portion, the spherical portion supporting table and the joint ring, and can adjust the rotation of the mirror barrel in the three axial directions around the center of the spherical portion, thereby achieving a compact-size design of the lens angle adjustment mechanism and the simplification of the structure thereof.